ABSTRACT ABS resins have wide application in the market, mainly in the manufacture of household appliances, telephones, automotive industry and others, and need to be processed by extrusion for the manufacture of products. The variables used in the process of extrusion of polymers have a direct influence on their mechanical properties. The objective of this study was to evaluate the different speeds of the extruder screw (15, 30, 45 and 60 rpm) on the mechanical properties of raw ABS after the extrusion process. Izod impact resistance and tensile tests, were also performed. The fractures of the samples tested by Izod impact were observed via optical microscopy, scanning electronic microscopy (SEM), and roughness was measured. Calorimetric tests (DSC) and thermogravimetry (TGA), as well as melt flow index (MFI), were also performed. The most significant results were observed for the extruder screw speed of 60 rpm. For the impact test, a reduction in impact energy of approximately 3% was observed, with the same result for tensile resistance. However, an increase in the value of the elastic modulus and the MFI was observed due to the increase in the degree of crystallinity, which was caused by the higher shear of the polymer mass in the screw of the extrusion equipment. Additionally, an atypical case occurred for the ABS polymer in the highest rotation, since it was the polymer that suffered the greatest shear in the polymer chains due to the degradation of the butadiene phase.

Abstract Solid residues from agroindustry often accumulate and cause environmental imbalance. An alternative to this is to use this residue as a reinforcement in polymers. The achievement of this work was to characterize a composite with a polystyrene matrix reinforced with Brazil nut shells residues. The residues were cleaned and ground to then produce the samples via injection molding with the proportions of 0%, 2.5% and 5% of load. The specimens were characterized using mechanical tensile testing and thermogravimetric analysis (TGA). The mechanical test showed that the composite with 2.5% of filler had greater stiffness and strength was improved by 5%. Thermal analysis showed an increase in the temperature for the beginning of the degradation of the M2.5 composite. The results confirm a potential application in the automotive industry for the polystyrene composite reinforced with Brazil nut shells.

The present work aims at the preliminary evaluation of the Paspalun repens macrophyte dry biomass adsorbent material of zinc (Zn) and copper (Cu) metals from water. The diversity of Species is due to the extensive aquatic environment where it is inserted. The Paspalun repens species comes from the Buiuçu lake located in the region of Parintins-Amazonas- Brazil. The macrophyte was dried in a mill and then a digestion through biomass microwaves was done before and after its exposure to the solutions containing different concentrations of zinc and copper (1.00, 1.50, 2.00, 3.00 mg mL-1 of metals) for a period of 48 hours. As a source of the metals, zinc sulfate (ZnSO4 7H2O) for zinc, and copper sulfate (CuSO4 5H2O) for copper were used as the source. As a result, the efficiency of Paspalun repens was observed in the metals removal, the highest removal percentage, of 29.67 and 37.07% in the leaves, whereas in the root it was 25.25 and 32.84% (at the concentration 1.0 and 2.0 mg/mL consequently), was of zinc, therefore the dry biomass of this species can be considered as a low cost alternative material in the removal of these heavy metals, contributing to the improvement of water quality.